Rensin insists that the smug belief in a "failure of half the country to know what's good for them" should be understood as "a psychological reaction to a profound shift in American political demography" - specifically, the shift of liberalism from "union halls and little magazines...into universities and major press, from the center of the country to its cities and elite enclaves". "The smug style arose" among the remaining liberal elites as an explanation for their abandonment. It is, that is to say, a political phenomenon that emerges from their rationalizations.
Nietzsche would argue that this gets it backwards. There are certainly smug liberals, but liberal smugness isn't really a significant or consequential force in politics - reactionaries just don't care what liberals actually think of them. What is significant, however, is the psychology of ressentiment among the oppressed. The conservative working class feels its powerlessness, feels its immiseration, and gets that elites are much better off; and for that reason, they are driven to rationalize and justify their opposition to their oppressors. The imputation of unearned entitlement and a superiority complex among elites is an inevitable expression of this.
The crucial thing to notice here is that the perception of smugness precedes any actual instances of smugness. If this is true, then no amount of diplomacy, outreach or sensitivity to the right-wing underclass will alleviate this particular problem; even if liberals are optimally gracious and understanding, the right will still invent reasons to read smugness into everything they do.
Nietzsche's law, and Jante's law
It seems clear to me that much of the criticism of Rensin's essay is coming from elites who feel indicted by the piece - as they should. But some of the more susbtantive criticism, I think, can be explained by the tension between these two theories of smugness. Nietzsche's argument does not require him to make claims about whether elite smugness is warranted - he simply treats it as a perception. Rensin, however, declares that the smug style's "case against its enemies" is "tenuous". This exposes him to the criticism that liberalism's case is often not tenuous - a point that Weird Twitter, of course, picked up on immediately.
That said, if we accept Nietzsche's conception of the problem, it seems that we have only two possible responses to the problem of smugness.
The first - Nietzsche's response - is to accept it as a fact of life, the inevitable expression of hierarchies that we will never be able to get rid of. If we insist that some people will always have more power than others, the disempowered will obviously always resent this, and will read smugness into any attempt the powerful make to justify themselves. Powerful people should not worry too much about this; haters gonna hate.
An alternative response, of course, would be to tear down socioeconomic hierarchies, empower the oppressed, and dethrone the elites. That would take away the superiority and inferiority complexes, the psychology of ressentiment, and the perceptions of smugness that all come as a package deal with hierarchy. This philosophical disposition has its own historical precedents, for example in the Law of Jante, which notably emerged in the markedly egalitarian societies of Scandinavia. Here, the left argues that you can't get rid of elite smugness by getting rid of the smugness - you have to get rid of the elites.
These divergent lines of thought have some obvious parallels in contemporary American politics. The left has clearly adopted the second position, which sees socioeconomic inequality as the primary (though not exclusive) driver of various forms of ressentiment. This is not a position that necessarily entails dismissing liberal positions as "tenuous", and neither does it have to ignore instances where liberals are indeed smug. Reactionaries, meanwhile, have clearly adopted Nietzsche's response, and concluded that hierarchy and smugness are here to stay, and even laudable.
What can liberals say to all of this? How can they escape Rensin's critique without embracing the hierarchies of Nietzsche and the right - or worse, accepting the radical egalitarianism of the left? Rensin writes,
This is not a call for civility. Manners are not enough. The smug style did not arise by accident, and it cannot be abolished with a little self-reproach.Liberals clearly believe that manners are enough, that civility and privilege-checking and all kinds of careful diplomacy can win over the underclass. Instead of abolishing hierarchy, liberals hope to eradicate perceptions of smugness with an ethic of magnanimity from above and grateful submission from below. This of course is embarrassingly naive, and amounts in practice to a de facto defense of Nietzsche's position. Liberals may nominally and even intentionally oppose smugness, but in their defense of hierarchy they guarantee that it will persist.